diff --git a/activesupport/lib/active_support/locale/en.yml b/activesupport/lib/active_support/locale/en.yml
index 997541fc79..0453883a79 100644
--- a/activesupport/lib/active_support/locale/en.yml
+++ b/activesupport/lib/active_support/locale/en.yml
@@ -45,7 +45,7 @@ en:
       # Number of decimals, behind the separator (the number 1 with a precision of 2 gives: 1.00)
       precision: 3
       # Determine how rounding is performed (see BigDecimal::mode)
-      round_mode: !ruby/sym default
+      round_mode: default
       # If set to true, precision will mean the number of significant digits instead
       # of the number of decimal digits (1234 with precision 2 becomes 1200, 1.23543 becomes 1.2)
       significant: false
diff --git a/activesupport/lib/active_support/number_helper/rounding_helper.rb b/activesupport/lib/active_support/number_helper/rounding_helper.rb
index cdf5535bd3..14deca13ea 100644
--- a/activesupport/lib/active_support/number_helper/rounding_helper.rb
+++ b/activesupport/lib/active_support/number_helper/rounding_helper.rb
@@ -13,7 +13,7 @@ def round(number)
         precision = absolute_precision(number)
         return number unless precision
 
-        rounded_number = convert_to_decimal(number).round(precision, options.fetch(:round_mode, :default))
+        rounded_number = convert_to_decimal(number).round(precision, options.fetch(:round_mode, :default).to_sym)
         rounded_number.zero? ? rounded_number.abs : rounded_number # prevent showing negative zeros
       end